N100CE

Substantial
None

DOUGLAS DC-6S/N: 44662

Accident Details

Date
Monday, November 25, 2013
NTSB Number
ANC14CA012
Location
Nuiqsut, AK
Event ID
20131220X70905
Coordinates
70.344169, -150.944717
Aircraft Damage
Substantial
Highest Injury
None
Fatalities
0
Serious Injuries
0
Minor Injuries
0
Uninjured
3
Total Aboard
3

Probable Cause and Findings

A load shift during takeoff, which resulted in substantial damage to the aft bulkhead and associated structures.

Aircraft Information

Registration
Make
DOUGLAS
Serial Number
44662
Engine Type
Reciprocating
Year Built
1953
Model / ICAO
DC-6DC6
Aircraft Type
Fixed Wing Multi Engine
No. of Engines
4
Seats
96
FAA Model
C-118A

Registered Owner (Current)

Name
TATONDUK OUTFITTERS LTD
Address
5525 AIRPORT INDUSTRIAL RD
City
FAIRBANKS
State / Zip Code
AK 99709-4470
Country
United States

Analysis

According to the operator, the purpose of the short, 22 minute flight was to deliver a load of oversized, oil drilling tools to a remote oil production site. The flightcrew reported that shortly after takeoff the first officer noticed that the airplane's elevator control movements appeared to be "momentarily stiff."

While en route to the destination, the flight engineer was asked to inspect the cargo, and he subsequently discovered that two of the four, 31-foot long oil drilling tools had shifted aft, damaging the aft pressure bulkhead. The captain did not declare an emergency, and the airplane landed at the destination without incident.

A postflight inspection revealed substantial damage to the aft pressure bulkhead assembly, as well as various frames, stringers and structural longerons. In addition, several attachments for the elevator flight control pulleys and flight control cable guides were damaged. The operator noted that the airplane's pressurization system had been removed years ago, when the airplane was converted to a cargo configuration.

The operator reported that after loading the airplane, just before departure, the crew inspected the five nylon strapping mechanisms that secured the four drilling tools to the floor of the airplane. The crew reported that all five of the nylon straps were tight before departure, but gathered that one or more had loosened slightly during taxi and takeoff, allowing two of the tools to shift aft during takeoff. The crew also noted that the drilling tools were covered with ice and snow, which likely aided in the tools sliding along the aluminum, diamond plate-covered floor of the airplane.

Data Source

Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# ANC14CA012